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You can't teach an old dog new tricks.
Literal
Old-dog [to-に] new tricks [topic-は] can't-teach.
The Japanese rendering of the well-known English proverb 'you can't teach an old dog new tricks,' using everyday 教える ('to teach'). 老犬 ('old dog') and 新しい芸 ('new tricks/feats' — 芸 covers performing-arts skills as well as animal tricks) keep the source proverb's imagery. 教えられない is the potential negative of 教える: 'cannot teach.' The に marks the dog as the recipient/learner of the teaching; 新しい芸 takes contrastive は ('as for new tricks').